1. Field of the Invention
The invention relates to font data generators, and more particularly to a font data generator that generates bit map font data used for displaying, printing or the like from outline font data.
2. Description of the Related Art
State-of-the-art displays and printers must be able to handle multi-size characters, symbols, graphics, and the like. (The characters, symbols, graphics and the like will hereinafter be referred to collectively as the "characters.") If font data of each size is supplied in bit map form, the amount of such data will become enormous. To avoid this problem, outline font data is employed. The outline font data consists of coordinate data expressing respective points of outline segments. Only a single piece of outline font data is for every typeface. Based on such outline font data, bit map font data of a required size is generated. These font data generating systems have been proposed in Published Unexamined Japanese Patent Application Nos. 164992/1989 and 77089/1989.
The bit map font data is generated by enlarging or reducing an outline indicated by the outline font data to desired sizes, and filling the area inside the outline. In this case, for characters of a small dot size (a pixel size), their thin line portions have widths smaller than a single pixel, and this may cause faded and/or lost character strokes and lines.
To prevent this, (1) pixels for "rimming," i.e., pixel data expressing the entire outline segments are synthesized into the bit map font data generated by filling the area inside the outline, or (2) the outline is modified by hint information so that the width of the outline is not reduced to smaller than a single dot, and the bit map font data is generated from such modified outline data.
However, technique (1) brings about the problem of thickening the font in proportion to the pixel data expressing the outline segments even in characters of a normal size, i.e., a size free from blurs or losses of character strokes.
In technique (2) the processing of modifying the outline information is complicated, thus decreasing the processing speed. In addition, the data size is increased in proportion to the amount of the hint information.